Ballistic Equations Will Save Us All

Jeff Campbell, who nabbed the cover of POWDER's December 2011 issue with a surreal nighttime powder shot taken in Utah by Garrett Grove, has taken an unusual career path. He's getting a PhD. And not in just any run-of-the-mill program rigorous enough for academia's highest distinction. He's working with Professor Randy Ching from the University of Washington's Applied Biomechanics Lab and a forensics engineering firm, Design Engineering, to see if he can design safer terrain parks.

The idea started with Design Engineering, who gets called in after ski areas get sued for negligence associated with injured skiers or snowboarders to try and recreate the accident and determine its cause. They wanted a system for measuring the forces that a skier or rider experiences on the hill, mostly importantly when jumping in terrain parks. Jeff and his professor quickly realized the project could help them design jumps that are safer, and specifically ones that don't force loads of G forces on new riders unfamiliar with the technique who are susceptible to getting in the back seat on the takeoff and landing on their head or neck.

Up until this point, professional terrain park builders, like Snow Park Technologies, have designed their jumps using what's known as a “center of mass ballistic equation,” which treats the rider like a rolling cannonball, and not as a dynamic linkage with joints and limbs. While the equation is an obvious simplification of the reality of jumping, Campbell recognizes "it's the best of what's out there for now."

How Campbell and his professor hope to improve upon this method is more than a little complicated. First, his crew grabbed an off-the-shelf body suit tagged up with sensors that provide a virtual picture of real-time body movements. It's most typically used for CGI animation, either to make Seth McFarlane's body movements translate into those of a stuffed bear in Ted or to perfectly replicate Dwayne Wade's dunk in NBA 2K13. Then Campbell created the second part of the system, which measures the amount of flex in a board or skis during takeoff in order to see how much the flex affects a rider's trajectory. And finally, Campbell is developing a proprietary system that measures the forces and torques being felt at the feet.

"We know how the body moves, so we treat it as a linkage," Campbell said. "And if we know the forces and torques are at the feet, and we know how all the links move up the chain, then we can back-calculate what all the forces are at the knees and the hips and so on."

With all three systems integrated, the data collected should allow the team to model how different jumps profiles affect riders' body positioning in the air, and thus shine a light on jump profiles and jumping techniques that put riders' bodies in safer positions. A test run at Woodward with a snowboarder in only the body suit gave the team enough info to understand how crucial the degree of flexing in the back knee was to proper air form.

Campbell is currently trying to raise $25,000 to finish this system through a campaign on Microryza, which is like a Kickstarter for science projects. He's hoping to entice both those who care about terrain parks and those who make money off of them to contribute, with the ultimate goal of keeping new riders safe and terrain parks open and available. If all the money is raised, they'll be able to start testing different jump profiles on snow come December. Although outdoor testing has never been attempted with much of this technology, he’s hoping by next spring or summer, he’ll be able to use their data and modeling to design and build the "perfect" jump and test it against their hypothesis.

In the meantime, Campbell and his team are working with Design Engineering on another ski safety project which will measure whether tech-compatible touring boots release from alpine bindings at the same torque value as regular alpine boots. They're concerned with the growing number of skiers using tech boots for both touring and alpine binding systems since they've never been rigorously tested for use in both.